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Revision 1.331 by root, Tue Aug 31 01:00:48 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	76	module users into the same thing by forcing them to use the same event
66	model you use.	77	model you use.
67		78
68	For modules like POE or IO::Async (which is a total misnomer as it is	79	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	80	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	81	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	82	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	83	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	84	module are I<also> forced to use the same event loop you use.
74		85
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	86	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	87	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	88	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
78	your module uses one of those, every user of your module has to use it,	89	your module uses one of those, every user of your module has to use it,
79	too. But if your module uses AnyEvent, it works transparently with all	90	too. But if your module uses AnyEvent, it works transparently with all
80	event models it supports (including stuff like IO::Async, as long as those	91	event models it supports (including stuff like IO::Async, as long as those
81	use one of the supported event loops. It is trivial to add new event loops	92	use one of the supported event loops. It is easy to add new event loops
82	to AnyEvent, too, so it is future-proof).	93	to AnyEvent, too, so it is future-proof).
83		94
84	In addition to being free of having to use I<the one and only true event	95	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	96	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	97	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	98	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	99	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	100	technically possible.
90		101
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	102	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	103	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	109	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	110	model, you should I<not> use this module.
100		111
101	=head1 DESCRIPTION	112	=head1 DESCRIPTION
102		113
103	L<AnyEvent> provides an identical interface to multiple event loops. This	114	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	115	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	116	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	117	than one event loop cannot coexist peacefully).
107		118
108	The interface itself is vaguely similar, but not identical to the L<Event>	119	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	120	module.
110		121
111	During the first call of any watcher-creation method, the module tries	122	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	123	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	124	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	125	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	126	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	127	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	128	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	129	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		130
122	Because AnyEvent first checks for modules that are already loaded, loading	131	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	132	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	133	that model the default. For example:
125		134
…		…
127	use AnyEvent;	136	use AnyEvent;
128		137
129	# .. AnyEvent will likely default to Tk	138	# .. AnyEvent will likely default to Tk
130		139
131	The I<likely> means that, if any module loads another event model and	140	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	141	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	142	as very few modules hardcode event loops without announcing this very
		143	loudly.
134		144
135	The pure-perl implementation of AnyEvent is called	145	The pure-perl implementation of AnyEvent is called
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	146	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	147	explicitly and enjoy the high availability of that event loop :)
138		148
…		…
147	callback when the event occurs (of course, only when the event model	157	callback when the event occurs (of course, only when the event model
148	is in control).	158	is in control).
149		159
150	Note that B<callbacks must not permanently change global variables>	160	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	161	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	162	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	163	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	164	widely between event loops.
155		165
156	To disable the watcher you have to destroy it (e.g. by setting the	166	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	167	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	168	to it).
159		169
160	All watchers are created by calling a method on the C<AnyEvent> class.	170	All watchers are created by calling a method on the C<AnyEvent> class.
161		171
162	Many watchers either are used with "recursion" (repeating timers for	172	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	173	example), or need to refer to their watcher object in other ways.
164		174
165	An any way to achieve that is this pattern:	175	One way to achieve that is this pattern:
166		176
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	177	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	178	# you can use $w here, for example to undef it
169	undef $w;	179	undef $w;
170	});	180	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	182	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	183	my variables are only visible after the statement in which they are
174	declared.	184	declared.
175		185
176	=head2 I/O WATCHERS	186	=head2 I/O WATCHERS
		187
		188	$w = AnyEvent->io (
		189	fh => <filehandle_or_fileno>,
		190	poll => <"r" or "w">,
		191	cb => <callback>,
		192	);
177		193
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	194	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	195	with the following mandatory key-value pairs as arguments:
180		196
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	197	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		212
197	The I/O watcher might use the underlying file descriptor or a copy of it.	213	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	214	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	215	underlying file descriptor.
200		216
201	Some event loops issue spurious readyness notifications, so you should	217	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	218	always use non-blocking calls when reading/writing from/to your file
203	handles.	219	handles.
204		220
205	Example: wait for readability of STDIN, then read a line and disable the	221	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	222	watcher.
…		…
211	undef $w;	227	undef $w;
212	});	228	});
213		229
214	=head2 TIME WATCHERS	230	=head2 TIME WATCHERS
215		231
		232	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		233
		234	$w = AnyEvent->timer (
		235	after => <fractional_seconds>,
		236	interval => <fractional_seconds>,
		237	cb => <callback>,
		238	);
		239
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	240	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	241	method with the following mandatory arguments:
218		242
219	C<after> specifies after how many seconds (fractional values are	243	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	244	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		246
223	Although the callback might get passed parameters, their value and	247	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	248	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	249	callbacks cannot use arguments passed to time watcher callbacks.
226		250
227	The callback will normally be invoked once only. If you specify another	251	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	252	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	253	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	254	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	255	false value, then it is treated as if it were not specified at all.
232		256
233	The callback will be rescheduled before invoking the callback, but no	257	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	258	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	259	only approximate.
236		260
237	Example: fire an event after 7.7 seconds.	261	Example: fire an event after 7.7 seconds.
238		262
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	263	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		281
258	While most event loops expect timers to specified in a relative way, they	282	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	283	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	284	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	285	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	286	fire "after a second" might actually take six years to finally fire.
263		287
264	AnyEvent cannot compensate for this. The only event loop that is conscious	288	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	289	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	290	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	291	timers.
268		292
269	AnyEvent always prefers relative timers, if available, matching the	293	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	294	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	316	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	317	function to call when you want to know the current time.>
294		318
295	This function is also often faster then C<< AnyEvent->time >>, and	319	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	320	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	321	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		322
299	The rest of this section is only of relevance if you try to be very exact	323	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	324	with your timing; you can skip it without a bad conscience.
301		325
302	For a practical example of when these times differ, consider L<Event::Lib>	326	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	327	and L<EV> and the following set-up:
304		328
305	The event loop is running and has just invoked one of your callback at	329	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	330	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	331	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	332	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	333	after three seconds.
310		334
…		…
341	might affect timers and time-outs.	365	might affect timers and time-outs.
342		366
343	When this is the case, you can call this method, which will update the	367	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	368	event loop's idea of "current time".
345		369
		370	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		371	when mod_perl executes the script, then the event loop will have the wrong
		372	idea about the "current time" (being potentially far in the past, when the
		373	script ran the last time). In that case you should arrange a call to C<<
		374	AnyEvent->now_update >> each time the web server process wakes up again
		375	(e.g. at the start of your script, or in a handler).
		376
346	Note that updating the time I<might> cause some events to be handled.	377	Note that updating the time I<might> cause some events to be handled.
347		378
348	=back	379	=back
349		380
350	=head2 SIGNAL WATCHERS	381	=head2 SIGNAL WATCHERS
		382
		383	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		384
352	You can watch for signals using a signal watcher, C<signal> is the signal	385	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	386	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	387	callback to be invoked whenever a signal occurs.
355		388
…		…
368		401
369	This watcher might use C<%SIG> (depending on the event loop used),	402	This watcher might use C<%SIG> (depending on the event loop used),
370	so programs overwriting those signals directly will likely not work	403	so programs overwriting those signals directly will likely not work
371	correctly.	404	correctly.
372		405
		406	Example: exit on SIGINT
		407
		408	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		409
		410	=head3 Restart Behaviour
		411
		412	While restart behaviour is up to the event loop implementation, most will
		413	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		414	pure perl implementation).
		415
		416	=head3 Safe/Unsafe Signals
		417
		418	Perl signals can be either "safe" (synchronous to opcode handling) or
		419	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		420	latter might corrupt your memory.
		421
		422	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		423	i.e. they will not interrupt your running perl program but will only be
		424	called as part of the normal event handling (just like timer, I/O etc.
		425	callbacks, too).
		426
		427	=head3 Signal Races, Delays and Workarounds
		428
373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not	429	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
374	support attaching callbacks to signals, which is a pity, as you cannot do	430	callbacks to signals in a generic way, which is a pity, as you cannot
375	race-free signal handling in perl. AnyEvent will try to do it's best, but	431	do race-free signal handling in perl, requiring C libraries for
		432	this. AnyEvent will try to do its best, which means in some cases,
376	in some cases, signals will be delayed. The maximum time a signal might	433	signals will be delayed. The maximum time a signal might be delayed is
377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	434	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
378	seconds). This variable can be changed only before the first signal	435	variable can be changed only before the first signal watcher is created,
379	watcher is created, and should be left alone otherwise. Higher values	436	and should be left alone otherwise. This variable determines how often
		437	AnyEvent polls for signals (in case a wake-up was missed). Higher values
380	will cause fewer spurious wake-ups, which is better for power and CPU	438	will cause fewer spurious wake-ups, which is better for power and CPU
		439	saving.
		440
381	saving. All these problems can be avoided by installing the optional	441	All these problems can be avoided by installing the optional
382	L<Async::Interrupt> module.	442	L<Async::Interrupt> module, which works with most event loops. It will not
383		443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
384	Example: exit on SIGINT	444	(and not with L<POE> currently, as POE does its own workaround with
385		445	one-second latency). For those, you just have to suffer the delays.
386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
387		446
388	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
389		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
390	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
391		452
392	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
393	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
394	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
395	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
396		458
397	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
398	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
399	callback arguments.	461	callback arguments.
400		462
…		…
441	# do something else, then wait for process exit	503	# do something else, then wait for process exit
442	$done->recv;	504	$done->recv;
443		505
444	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
445		507
446	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
447	to do it instantly, but only when there is nothing better to do. This
448	"nothing better to do" is usually defined to be "no other events need
449	attention by the event loop".
450		509
451	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
452	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
453	events. Instead of blocking, the idle watcher is invoked.
454		512
455	Most event loops unfortunately do not really support idle watchers (only	513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
456	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
457	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
458		525
459	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
460	program is otherwise idle:	527	program is otherwise idle:
…		…
476	});	543	});
477	});	544	});
478		545
479	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
480		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
481	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
482	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
483	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
484		556
485	AnyEvent is slightly different: it expects somebody else to run the event	557	AnyEvent is slightly different: it expects somebody else to run the event
486	loop and will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
487		559
488	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
489	because they represent a condition that must become true.	561	they represent a condition that must become true.
490		562
491	Now is probably a good time to look at the examples further below.	563	Now is probably a good time to look at the examples further below.
492		564
493	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
494	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
499	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
500	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
501	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
502	->send >> method).	574	->send >> method).
503		575
504	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
505	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
506	in time where multiple outstanding events have been processed. And yet	578
507	another way to call them is transactions - each condition variable can be	579	=over 4
508	used to represent a transaction, which finishes at some point and delivers	580
509	a result.	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
		582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
510		599
511	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
512	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
513	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
514	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
527		616
528	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
529	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
530	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
531	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
532	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
533		622
534	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
535	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
536	for the send to occur.	625	for the send to occur.
537		626
538	Example: wait for a timer.	627	Example: wait for a timer.
539		628
540	# wait till the result is ready	629	# condition: "wait till the timer is fired"
541	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
542		631
543	# do something such as adding a timer	632	# create the timer - we could wait for, say
544	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
545	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
546	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
547	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
548	after => 1,	637	after => 1,
549	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
550	);	639	);
551		640
552	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
553	# calls -<send	642	# calls ->send
554	$result_ready->recv;	643	$timer_fired->recv;
555		644
556	Example: wait for a timer, but take advantage of the fact that condition	645	Example: wait for a timer, but take advantage of the fact that condition
557	variables are also callable directly.	646	variables are also callable directly.
558		647
559	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
602	they were a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
603	C<send>.	692	C<send>.
604		693
605	=item $cv->croak ($error)	694	=item $cv->croak ($error)
606		695
607	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
608	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
609		698
610	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
611	user/consumer. Doing it this way instead of calling C<croak> directly	700	user/consumer. Doing it this way instead of calling C<croak> directly
612	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
613	diagnoses the error at the place where the result is expected, and not	702	diagnoses the error at the place where the result is expected, and not
614	deep in some event clalback without connection to the actual code causing	703	deep in some event callback with no connection to the actual code causing
615	the problem.	704	the problem.
616		705
617	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
618		707
619	=item $cv->end	708	=item $cv->end
…		…
622	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
623	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
624		713
625	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
626	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
627	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
628	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
629	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
630		720
631	You can think of C<< $cv->send >> giving you an OR condition (one call	721	You can think of C<< $cv->send >> giving you an OR condition (one call
632	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
633	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
634		724
…		…
656	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
657	sending.	747	sending.
658		748
659	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
660	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
661	begung can potentially be zero:	751	begun can potentially be zero:
662		752
663	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
664		754
665	my %result;	755	my %result;
666	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
667		757
668	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
669	$cv->begin;	759	$cv->begin;
670	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
671	$result{$host} = ...;	761	$result{$host} = ...;
…		…
687	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
688	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
689	doesn't execute once).	779	doesn't execute once).
690		780
691	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
692	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
693	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
694	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
695	call C<end>.	785	call C<end>.
696		786
697	=back	787	=back
…		…
704	=over 4	794	=over 4
705		795
706	=item $cv->recv	796	=item $cv->recv
707		797
708	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
709	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
710	normally.	800	normally.
711		801
712	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
713	will return immediately.	803	will return immediately.
714		804
…		…
731	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
732	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
733	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
734	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
735		825
736	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
737	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
738	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
739	waits otherwise.	829	waits otherwise.
740		830
741	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
747		837
748	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
749	replaces it before doing so.	839	replaces it before doing so.
750		840
751	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
752	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
753	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
754	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
755		846
756	=back	847	=back
757		848
758	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
759		850
…		…
762	=over 4	853	=over 4
763		854
764	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
765		856
766	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
767	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
768	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
769	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
770		861
771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
774		864
775	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
776		866
777	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
778	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
779	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
780	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
781	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
782		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
783	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
784	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
786	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
787		879
788	=item Backends with special needs.	880	=item Backends with special needs.
789		881
790	Qt requires the Qt::Application to be instantiated first, but will	882	Qt requires the Qt::Application to be instantiated first, but will
791	otherwise be picked up automatically. As long as the main program	883	otherwise be picked up automatically. As long as the main program
…		…
796		888
797	Support for IO::Async can only be partial, as it is too broken and	889	Support for IO::Async can only be partial, as it is too broken and
798	architecturally limited to even support the AnyEvent API. It also	890	architecturally limited to even support the AnyEvent API. It also
799	is the only event loop that needs the loop to be set explicitly, so	891	is the only event loop that needs the loop to be set explicitly, so
800	it can only be used by a main program knowing about AnyEvent. See	892	it can only be used by a main program knowing about AnyEvent. See
801	L<AnyEvent::Impl::Async> for the gory details.	893	L<AnyEvent::Impl::IOAsync> for the gory details.
802		894
803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.	895	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
804		896
805	=item Event loops that are indirectly supported via other backends.	897	=item Event loops that are indirectly supported via other backends.
806		898
…		…
834	Contains C<undef> until the first watcher is being created, before the	926	Contains C<undef> until the first watcher is being created, before the
835	backend has been autodetected.	927	backend has been autodetected.
836		928
837	Afterwards it contains the event model that is being used, which is the	929	Afterwards it contains the event model that is being used, which is the
838	name of the Perl class implementing the model. This class is usually one	930	name of the Perl class implementing the model. This class is usually one
839	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	931	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
840	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	932	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
841	will be C<urxvt::anyevent>).	933	will be C<urxvt::anyevent>).
842		934
843	=item AnyEvent::detect	935	=item AnyEvent::detect
844		936
845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	937	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
846	if necessary. You should only call this function right before you would	938	if necessary. You should only call this function right before you would
847	have created an AnyEvent watcher anyway, that is, as late as possible at	939	have created an AnyEvent watcher anyway, that is, as late as possible at
848	runtime, and not e.g. while initialising of your module.	940	runtime, and not e.g. during initialisation of your module.
849		941
850	If you need to do some initialisation before AnyEvent watchers are	942	If you need to do some initialisation before AnyEvent watchers are
851	created, use C<post_detect>.	943	created, use C<post_detect>.
852		944
853	=item $guard = AnyEvent::post_detect { BLOCK }	945	=item $guard = AnyEvent::post_detect { BLOCK }
854		946
855	Arranges for the code block to be executed as soon as the event model is	947	Arranges for the code block to be executed as soon as the event model is
856	autodetected (or immediately if this has already happened).	948	autodetected (or immediately if that has already happened).
857		949
858	The block will be executed I<after> the actual backend has been detected	950	The block will be executed I<after> the actual backend has been detected
859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	951	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	952	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
861	other initialisations - see the sources of L<AnyEvent::Strict> or	953	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
865	event module detection too early, for example, L<AnyEvent::AIO> creates	957	event module detection too early, for example, L<AnyEvent::AIO> creates
866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	958	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
867	avoid autodetecting the event module at load time.	959	avoid autodetecting the event module at load time.
868		960
869	If called in scalar or list context, then it creates and returns an object	961	If called in scalar or list context, then it creates and returns an object
870	that automatically removes the callback again when it is destroyed. See	962	that automatically removes the callback again when it is destroyed (or
		963	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
871	L<Coro::BDB> for a case where this is useful.	964	a case where this is useful.
		965
		966	Example: Create a watcher for the IO::AIO module and store it in
		967	C<$WATCHER>, but do so only do so after the event loop is initialised.
		968
		969	our WATCHER;
		970
		971	my $guard = AnyEvent::post_detect {
		972	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		973	};
		974
		975	# the ||= is important in case post_detect immediately runs the block,
		976	# as to not clobber the newly-created watcher. assigning both watcher and
		977	# post_detect guard to the same variable has the advantage of users being
		978	# able to just C<undef $WATCHER> if the watcher causes them grief.
		979
		980	$WATCHER ||= $guard;
872		981
873	=item @AnyEvent::post_detect	982	=item @AnyEvent::post_detect
874		983
875	If there are any code references in this array (you can C<push> to it	984	If there are any code references in this array (you can C<push> to it
876	before or after loading AnyEvent), then they will called directly after	985	before or after loading AnyEvent), then they will be called directly
877	the event loop has been chosen.	986	after the event loop has been chosen.
878		987
879	You should check C<$AnyEvent::MODEL> before adding to this array, though:	988	You should check C<$AnyEvent::MODEL> before adding to this array, though:
880	if it is defined then the event loop has already been detected, and the	989	if it is defined then the event loop has already been detected, and the
881	array will be ignored.	990	array will be ignored.
882		991
883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	992	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
884	it,as it takes care of these details.	993	it, as it takes care of these details.
885		994
886	This variable is mainly useful for modules that can do something useful	995	This variable is mainly useful for modules that can do something useful
887	when AnyEvent is used and thus want to know when it is initialised, but do	996	when AnyEvent is used and thus want to know when it is initialised, but do
888	not need to even load it by default. This array provides the means to hook	997	not need to even load it by default. This array provides the means to hook
889	into AnyEvent passively, without loading it.	998	into AnyEvent passively, without loading it.
890		999
		1000	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1001	together, you could put this into Coro (this is the actual code used by
		1002	Coro to accomplish this):
		1003
		1004	if (defined $AnyEvent::MODEL) {
		1005	# AnyEvent already initialised, so load Coro::AnyEvent
		1006	require Coro::AnyEvent;
		1007	} else {
		1008	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1009	# as soon as it is
		1010	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1011	}
		1012
891	=back	1013	=back
892		1014
893	=head1 WHAT TO DO IN A MODULE	1015	=head1 WHAT TO DO IN A MODULE
894		1016
895	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1017	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
905	because it will stall the whole program, and the whole point of using	1027	because it will stall the whole program, and the whole point of using
906	events is to stay interactive.	1028	events is to stay interactive.
907		1029
908	It is fine, however, to call C<< ->recv >> when the user of your module	1030	It is fine, however, to call C<< ->recv >> when the user of your module
909	requests it (i.e. if you create a http request object ad have a method	1031	requests it (i.e. if you create a http request object ad have a method
910	called C<results> that returns the results, it should call C<< ->recv >>	1032	called C<results> that returns the results, it may call C<< ->recv >>
911	freely, as the user of your module knows what she is doing. always).	1033	freely, as the user of your module knows what she is doing. Always).
912		1034
913	=head1 WHAT TO DO IN THE MAIN PROGRAM	1035	=head1 WHAT TO DO IN THE MAIN PROGRAM
914		1036
915	There will always be a single main program - the only place that should	1037	There will always be a single main program - the only place that should
916	dictate which event model to use.	1038	dictate which event model to use.
917		1039
918	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1040	If the program is not event-based, it need not do anything special, even
919	do anything special (it does not need to be event-based) and let AnyEvent	1041	when it depends on a module that uses an AnyEvent. If the program itself
920	decide which implementation to chose if some module relies on it.	1042	uses AnyEvent, but does not care which event loop is used, all it needs
		1043	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1044	available loop implementation.
921		1045
922	If the main program relies on a specific event model - for example, in	1046	If the main program relies on a specific event model - for example, in
923	Gtk2 programs you have to rely on the Glib module - you should load the	1047	Gtk2 programs you have to rely on the Glib module - you should load the
924	event module before loading AnyEvent or any module that uses it: generally	1048	event module before loading AnyEvent or any module that uses it: generally
925	speaking, you should load it as early as possible. The reason is that	1049	speaking, you should load it as early as possible. The reason is that
926	modules might create watchers when they are loaded, and AnyEvent will	1050	modules might create watchers when they are loaded, and AnyEvent will
927	decide on the event model to use as soon as it creates watchers, and it	1051	decide on the event model to use as soon as it creates watchers, and it
928	might chose the wrong one unless you load the correct one yourself.	1052	might choose the wrong one unless you load the correct one yourself.
929		1053
930	You can chose to use a pure-perl implementation by loading the	1054	You can chose to use a pure-perl implementation by loading the
931	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1055	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
932	everywhere, but letting AnyEvent chose the model is generally better.	1056	everywhere, but letting AnyEvent chose the model is generally better.
933		1057
…		…
951	=head1 OTHER MODULES	1075	=head1 OTHER MODULES
952		1076
953	The following is a non-exhaustive list of additional modules that use	1077	The following is a non-exhaustive list of additional modules that use
954	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1078	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
955	modules and other event loops in the same program. Some of the modules	1079	modules and other event loops in the same program. Some of the modules
956	come with AnyEvent, most are available via CPAN.	1080	come as part of AnyEvent, the others are available via CPAN.
957		1081
958	=over 4	1082	=over 4
959		1083
960	=item L<AnyEvent::Util>	1084	=item L<AnyEvent::Util>
961		1085
962	Contains various utility functions that replace often-used but blocking	1086	Contains various utility functions that replace often-used blocking
963	functions such as C<inet_aton> by event-/callback-based versions.	1087	functions such as C<inet_aton> with event/callback-based versions.
964		1088
965	=item L<AnyEvent::Socket>	1089	=item L<AnyEvent::Socket>
966		1090
967	Provides various utility functions for (internet protocol) sockets,	1091	Provides various utility functions for (internet protocol) sockets,
968	addresses and name resolution. Also functions to create non-blocking tcp	1092	addresses and name resolution. Also functions to create non-blocking tcp
…		…
970		1094
971	=item L<AnyEvent::Handle>	1095	=item L<AnyEvent::Handle>
972		1096
973	Provide read and write buffers, manages watchers for reads and writes,	1097	Provide read and write buffers, manages watchers for reads and writes,
974	supports raw and formatted I/O, I/O queued and fully transparent and	1098	supports raw and formatted I/O, I/O queued and fully transparent and
975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1099	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
976		1100
977	=item L<AnyEvent::DNS>	1101	=item L<AnyEvent::DNS>
978		1102
979	Provides rich asynchronous DNS resolver capabilities.	1103	Provides rich asynchronous DNS resolver capabilities.
980		1104
		1105	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1106
		1107	Implement event-based interfaces to the protocols of the same name (for
		1108	the curious, IGS is the International Go Server and FCP is the Freenet
		1109	Client Protocol).
		1110
		1111	=item L<AnyEvent::Handle::UDP>
		1112
		1113	Here be danger!
		1114
		1115	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1116	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1117	its use of a stream-based API with a protocol that isn't streamable, that
		1118	the only way to improve it is to delete it.
		1119
		1120	It features data corruption (but typically only under load) and general
		1121	confusion. On top, the author is not only clueless about UDP but also
		1122	fact-resistant - some gems of his understanding: "connect doesn't work
		1123	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1124	packets", "I don't need to implement proper error checking as UDP doesn't
		1125	support error checking" and so on - he doesn't even understand what's
		1126	wrong with his module when it is explained to him.
		1127
981	=item L<AnyEvent::HTTP>	1128	=item L<AnyEvent::DBI>
982		1129
983	A simple-to-use HTTP library that is capable of making a lot of concurrent	1130	Executes L<DBI> requests asynchronously in a proxy process for you,
984	HTTP requests.	1131	notifying you in an event-based way when the operation is finished.
		1132
		1133	=item L<AnyEvent::AIO>
		1134
		1135	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1136	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1137	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1138	file I/O, and much more.
985		1139
986	=item L<AnyEvent::HTTPD>	1140	=item L<AnyEvent::HTTPD>
987		1141
988	Provides a simple web application server framework.	1142	A simple embedded webserver.
989		1143
990	=item L<AnyEvent::FastPing>	1144	=item L<AnyEvent::FastPing>
991		1145
992	The fastest ping in the west.	1146	The fastest ping in the west.
993
994	=item L<AnyEvent::DBI>
995
996	Executes L<DBI> requests asynchronously in a proxy process.
997
998	=item L<AnyEvent::AIO>
999
1000	Truly asynchronous I/O, should be in the toolbox of every event
1001	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1002	together.
1003
1004	=item L<AnyEvent::BDB>
1005
1006	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1007	L<BDB> and AnyEvent together.
1008
1009	=item L<AnyEvent::GPSD>
1010
1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
1012
1013	=item L<AnyEvent::IRC>
1014
1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1016
1017	=item L<AnyEvent::XMPP>
1018
1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1020	Net::XMPP2>.
1021
1022	=item L<AnyEvent::IGS>
1023
1024	A non-blocking interface to the Internet Go Server protocol (used by
1025	L<App::IGS>).
1026
1027	=item L<Net::FCP>
1028
1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1030	of AnyEvent.
1031
1032	=item L<Event::ExecFlow>
1033
1034	High level API for event-based execution flow control.
1035		1147
1036	=item L<Coro>	1148	=item L<Coro>
1037		1149
1038	Has special support for AnyEvent via L<Coro::AnyEvent>.	1150	Has special support for AnyEvent via L<Coro::AnyEvent>.
1039		1151
…		…
1043		1155
1044	package AnyEvent;	1156	package AnyEvent;
1045		1157
1046	# basically a tuned-down version of common::sense	1158	# basically a tuned-down version of common::sense
1047	sub common_sense {	1159	sub common_sense {
1048	# no warnings	1160	# from common:.sense 1.0
1049	${^WARNING_BITS} ^= ${^WARNING_BITS};	1161	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1050	# use strict vars subs	1162	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1051	$^H |= 0x00000600;	1163	$^H |= 0x00000600;
1052	}	1164	}
1053		1165
1054	BEGIN { AnyEvent::common_sense }	1166	BEGIN { AnyEvent::common_sense }
1055		1167
1056	use Carp ();	1168	use Carp ();
1057		1169
1058	our $VERSION = 4.85;	1170	our $VERSION = '5.271';
1059	our $MODEL;	1171	our $MODEL;
1060		1172
1061	our $AUTOLOAD;	1173	our $AUTOLOAD;
1062	our @ISA;	1174	our @ISA;
1063		1175
1064	our @REGISTRY;	1176	our @REGISTRY;
1065		1177
1066	our $WIN32;
1067
1068	our $VERBOSE;	1178	our $VERBOSE;
1069		1179
1070	BEGIN {	1180	BEGIN {
1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1181	require "AnyEvent/constants.pl";
		1182
1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1183	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1073		1184
1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1185	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1075	if ${^TAINT};	1186	if ${^TAINT};
1076		1187
1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1188	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1088	for reverse split /\s*,\s*/,	1199	for reverse split /\s*,\s*/,
1089	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1200	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1090	}	1201	}
1091		1202
1092	my @models = (	1203	my @models = (
1093	[EV:: => AnyEvent::Impl::EV::],	1204	[EV:: => AnyEvent::Impl::EV:: , 1],
1094	[Event:: => AnyEvent::Impl::Event::],
1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1205	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1096	# everything below here will not be autoprobed	1206	# everything below here will not (normally) be autoprobed
1097	# as the pureperl backend should work everywhere	1207	# as the pureperl backend should work everywhere
1098	# and is usually faster	1208	# and is usually faster
		1209	[Event:: => AnyEvent::Impl::Event::, 1],
1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1210	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1211	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1212	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1213	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1214	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1215	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1104	[Wx:: => AnyEvent::Impl::POE::],	1216	[Wx:: => AnyEvent::Impl::POE::],
1105	[Prima:: => AnyEvent::Impl::POE::],	1217	[Prima:: => AnyEvent::Impl::POE::],
1106	# IO::Async is just too broken - we would need workarounds for its	1218	# IO::Async is just too broken - we would need workarounds for its
1107	# byzantine signal and broken child handling, among others.	1219	# byzantine signal and broken child handling, among others.
1108	# IO::Async is rather hard to detect, as it doesn't have any	1220	# IO::Async is rather hard to detect, as it doesn't have any
1109	# obvious default class.	1221	# obvious default class.
1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1222	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1223	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1224	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1225	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1113	);	1226	);
1114		1227
1115	our %method = map +($_ => 1),	1228	our %method = map +($_ => 1),
1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1229	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1117		1230
1118	our @post_detect;	1231	our @post_detect;
1119		1232
1120	sub post_detect(&) {	1233	sub post_detect(&) {
1121	my ($cb) = @_;	1234	my ($cb) = @_;
1122		1235
1123	if ($MODEL) {
1124	$cb->();
1125
1126	1
1127	} else {
1128	push @post_detect, $cb;	1236	push @post_detect, $cb;
1129		1237
1130	defined wantarray	1238	defined wantarray
1131	? bless \$cb, "AnyEvent::Util::postdetect"	1239	? bless \$cb, "AnyEvent::Util::postdetect"
1132	: ()	1240	: ()
1133	}
1134	}	1241	}
1135		1242
1136	sub AnyEvent::Util::postdetect::DESTROY {	1243	sub AnyEvent::Util::postdetect::DESTROY {
1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1244	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1138	}	1245	}
1139		1246
1140	sub detect() {	1247	sub detect() {
		1248	# free some memory
		1249	*detect = sub () { $MODEL };
		1250
		1251	local $!; # for good measure
		1252	local $SIG{__DIE__};
		1253
		1254	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1255	my $model = "AnyEvent::Impl::$1";
		1256	if (eval "require $model") {
		1257	$MODEL = $model;
		1258	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1259	} else {
		1260	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1261	}
		1262	}
		1263
		1264	# check for already loaded models
1141	unless ($MODEL) {	1265	unless ($MODEL) {
1142	local $SIG{__DIE__};	1266	for (@REGISTRY, @models) {
1143		1267	my ($package, $model) = @$_;
1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1268	if (${"$package\::VERSION"} > 0) {
1145	my $model = "AnyEvent::Impl::$1";
1146	if (eval "require $model") {	1269	if (eval "require $model") {
1147	$MODEL = $model;	1270	$MODEL = $model;
1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1271	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1149	} else {	1272	last;
1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1273	}
1151	}	1274	}
1152	}	1275	}
1153		1276
1154	# check for already loaded models
1155	unless ($MODEL) {	1277	unless ($MODEL) {
		1278	# try to autoload a model
1156	for (@REGISTRY, @models) {	1279	for (@REGISTRY, @models) {
1157	my ($package, $model) = @$_;	1280	my ($package, $model, $autoload) = @$_;
		1281	if (
		1282	$autoload
		1283	and eval "require $package"
1158	if (${"$package\::VERSION"} > 0) {	1284	and ${"$package\::VERSION"} > 0
1159	if (eval "require $model") {	1285	and eval "require $model"
		1286	) {
1160	$MODEL = $model;	1287	$MODEL = $model;
1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1288	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1162	last;	1289	last;
1163	}
1164	}	1290	}
1165	}	1291	}
1166		1292
1167	unless ($MODEL) {
1168	# try to load a model
1169
1170	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;
1172	if (eval "require $package"
1173	and ${"$package\::VERSION"} > 0
1174	and eval "require $model") {
1175	$MODEL = $model;
1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1177	last;
1178	}
1179	}
1180
1181	$MODEL	1293	$MODEL
1182	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1294	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1183	}
1184	}	1295	}
1185
1186	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1187
1188	unshift @ISA, $MODEL;
1189
1190	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1191
1192	(shift @post_detect)->() while @post_detect;
1193	}	1296	}
		1297
		1298	@models = (); # free probe data
		1299
		1300	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1301	unshift @ISA, $MODEL;
		1302
		1303	# now nuke some methods that are overriden by the backend.
		1304	# SUPER is not allowed.
		1305	for (qw(time signal child idle)) {
		1306	undef &{"AnyEvent::Base::$_"}
		1307	if defined &{"$MODEL\::$_"};
		1308	}
		1309
		1310	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1311
		1312	(shift @post_detect)->() while @post_detect;
		1313
		1314	*post_detect = sub(&) {
		1315	shift->();
		1316
		1317	undef
		1318	};
1194		1319
1195	$MODEL	1320	$MODEL
1196	}	1321	}
1197		1322
1198	sub AUTOLOAD {	1323	sub AUTOLOAD {
1199	(my $func = $AUTOLOAD) =~ s/.*://;	1324	(my $func = $AUTOLOAD) =~ s/.*://;
1200		1325
1201	$method{$func}	1326	$method{$func}
1202	or Carp::croak "$func: not a valid method for AnyEvent objects";	1327	or Carp::croak "$func: not a valid AnyEvent class method";
1203		1328
1204	detect unless $MODEL;	1329	detect;
1205		1330
1206	my $class = shift;	1331	my $class = shift;
1207	$class->$func (@_);	1332	$class->$func (@_);
1208	}	1333	}
1209		1334
…		…
1222	# we assume CLOEXEC is already set by perl in all important cases	1347	# we assume CLOEXEC is already set by perl in all important cases
1223		1348
1224	($fh2, $rw)	1349	($fh2, $rw)
1225	}	1350	}
1226		1351
		1352	=head1 SIMPLIFIED AE API
		1353
		1354	Starting with version 5.0, AnyEvent officially supports a second, much
		1355	simpler, API that is designed to reduce the calling, typing and memory
		1356	overhead by using function call syntax and a fixed number of parameters.
		1357
		1358	See the L<AE> manpage for details.
		1359
		1360	=cut
		1361
		1362	package AE;
		1363
		1364	our $VERSION = $AnyEvent::VERSION;
		1365
		1366	# fall back to the main API by default - backends and AnyEvent::Base
		1367	# implementations can overwrite these.
		1368
		1369	sub io($$$) {
		1370	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1371	}
		1372
		1373	sub timer($$$) {
		1374	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1375	}
		1376
		1377	sub signal($$) {
		1378	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1379	}
		1380
		1381	sub child($$) {
		1382	AnyEvent->child (pid => $_[0], cb => $_[1])
		1383	}
		1384
		1385	sub idle($) {
		1386	AnyEvent->idle (cb => $_[0])
		1387	}
		1388
		1389	sub cv(;&) {
		1390	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1391	}
		1392
		1393	sub now() {
		1394	AnyEvent->now
		1395	}
		1396
		1397	sub now_update() {
		1398	AnyEvent->now_update
		1399	}
		1400
		1401	sub time() {
		1402	AnyEvent->time
		1403	}
		1404
1227	package AnyEvent::Base;	1405	package AnyEvent::Base;
1228		1406
1229	# default implementations for many methods	1407	# default implementations for many methods
1230		1408
1231	sub _time {	1409	sub time {
		1410	eval q{ # poor man's autoloading {}
1232	# probe for availability of Time::HiRes	1411	# probe for availability of Time::HiRes
1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1412	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1413	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1235	*_time = \&Time::HiRes::time;	1414	*AE::time = \&Time::HiRes::time;
1236	# if (eval "use POSIX (); (POSIX::times())...	1415	# if (eval "use POSIX (); (POSIX::times())...
1237	} else {	1416	} else {
1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1417	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1239	*_time = sub { time }; # epic fail	1418	*AE::time = sub (){ time }; # epic fail
		1419	}
		1420
		1421	*time = sub { AE::time }; # different prototypes
1240	}	1422	};
		1423	die if $@;
1241		1424
1242	&_time	1425	&time
1243	}	1426	}
1244		1427
1245	sub time { _time }	1428	*now = \&time;
1246	sub now { _time }	1429
1247	sub now_update { }	1430	sub now_update { }
1248		1431
1249	# default implementation for ->condvar	1432	# default implementation for ->condvar
1250		1433
1251	sub condvar {	1434	sub condvar {
		1435	eval q{ # poor man's autoloading {}
		1436	*condvar = sub {
1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1437	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1438	};
		1439
		1440	*AE::cv = sub (;&) {
		1441	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1442	};
		1443	};
		1444	die if $@;
		1445
		1446	&condvar
1253	}	1447	}
1254		1448
1255	# default implementation for ->signal	1449	# default implementation for ->signal
1256		1450
1257	our $HAVE_ASYNC_INTERRUPT;	1451	our $HAVE_ASYNC_INTERRUPT;
		1452
		1453	sub _have_async_interrupt() {
		1454	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1455	&& eval "use Async::Interrupt 1.02 (); 1")
		1456	unless defined $HAVE_ASYNC_INTERRUPT;
		1457
		1458	$HAVE_ASYNC_INTERRUPT
		1459	}
		1460
1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1461	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1259	our (%SIG_ASY, %SIG_ASY_W);	1462	our (%SIG_ASY, %SIG_ASY_W);
1260	our ($SIG_COUNT, $SIG_TW);	1463	our ($SIG_COUNT, $SIG_TW);
1261		1464
1262	sub _signal_exec {	1465	# install a dummy wakeup watcher to reduce signal catching latency
1263	$HAVE_ASYNC_INTERRUPT	1466	# used by Impls
1264	? $SIGPIPE_R->drain	1467	sub _sig_add() {
1265	: sysread $SIGPIPE_R, my $dummy, 9;	1468	unless ($SIG_COUNT++) {
		1469	# try to align timer on a full-second boundary, if possible
		1470	my $NOW = AE::now;
1266		1471
1267	while (%SIG_EV) {	1472	$SIG_TW = AE::timer
1268	for (keys %SIG_EV) {	1473	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1269	delete $SIG_EV{$_};	1474	$MAX_SIGNAL_LATENCY,
1270	$_->() for values %{ $SIG_CB{$_} || {} };	1475	sub { } # just for the PERL_ASYNC_CHECK
1271	}	1476	;
1272	}	1477	}
1273	}	1478	}
1274		1479
1275	sub _signal {	1480	sub _sig_del {
1276	my (undef, %arg) = @_;
1277
1278	my $signal = uc $arg{signal}
1279	or Carp::croak "required option 'signal' is missing";
1280
1281	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1282
1283	if ($HAVE_ASYNC_INTERRUPT) {
1284	# async::interrupt
1285
1286	$SIG_ASY{$signal} ||= do {
1287	my $asy = new Async::Interrupt
1288	cb => sub { undef $SIG_EV{$signal} },
1289	signal => $signal,
1290	pipe => [$SIGPIPE_R->filenos],
1291	;
1292	$asy->pipe_autodrain (0);
1293
1294	$asy
1295	};
1296
1297	} else {
1298	# pure perl
1299
1300	$SIG{$signal} ||= sub {
1301	local $!;
1302	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1303	undef $SIG_EV{$signal};
1304	};
1305
1306	# can't do signal processing without introducing races in pure perl,
1307	# so limit the signal latency.
1308	++$SIG_COUNT;
1309	$SIG_TW ||= AnyEvent->timer (
1310	after => $MAX_SIGNAL_LATENCY,
1311	interval => $MAX_SIGNAL_LATENCY,
1312	cb => sub { }, # just for the PERL_ASYNC_CHECK
1313	);
1314	}
1315
1316	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1317	}
1318
1319	sub signal {
1320	# probe for availability of Async::Interrupt
1321	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1322	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1323
1324	$HAVE_ASYNC_INTERRUPT = 1;
1325	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1326	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1327
1328	} else {
1329	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1330
1331	require Fcntl;
1332
1333	if (AnyEvent::WIN32) {
1334	require AnyEvent::Util;
1335
1336	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1337	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1338	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1339	} else {
1340	pipe $SIGPIPE_R, $SIGPIPE_W;
1341	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1342	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1343
1344	# not strictly required, as $^F is normally 2, but let's make sure...
1345	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1346	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1347	}
1348
1349	$SIGPIPE_R
1350	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1351
1352	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1353	}
1354
1355	*signal = \&_signal;
1356	&signal
1357	}
1358
1359	sub AnyEvent::Base::signal::DESTROY {
1360	my ($signal, $cb) = @{$_[0]};
1361
1362	undef $SIG_TW	1481	undef $SIG_TW
1363	unless --$SIG_COUNT;	1482	unless --$SIG_COUNT;
		1483	}
1364		1484
		1485	our $_sig_name_init; $_sig_name_init = sub {
		1486	eval q{ # poor man's autoloading {}
		1487	undef $_sig_name_init;
		1488
		1489	if (_have_async_interrupt) {
		1490	*sig2num = \&Async::Interrupt::sig2num;
		1491	*sig2name = \&Async::Interrupt::sig2name;
		1492	} else {
		1493	require Config;
		1494
		1495	my %signame2num;
		1496	@signame2num{ split ' ', $Config::Config{sig_name} }
		1497	= split ' ', $Config::Config{sig_num};
		1498
		1499	my @signum2name;
		1500	@signum2name[values %signame2num] = keys %signame2num;
		1501
		1502	*sig2num = sub($) {
		1503	$_[0] > 0 ? shift : $signame2num{+shift}
		1504	};
		1505	*sig2name = sub ($) {
		1506	$_[0] > 0 ? $signum2name[+shift] : shift
		1507	};
		1508	}
		1509	};
		1510	die if $@;
		1511	};
		1512
		1513	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1514	sub sig2name($) { &$_sig_name_init; &sig2name }
		1515
		1516	sub signal {
		1517	eval q{ # poor man's autoloading {}
		1518	# probe for availability of Async::Interrupt
		1519	if (_have_async_interrupt) {
		1520	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1521
		1522	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1523	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1524
		1525	} else {
		1526	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1527
		1528	if (AnyEvent::WIN32) {
		1529	require AnyEvent::Util;
		1530
		1531	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1533	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1534	} else {
		1535	pipe $SIGPIPE_R, $SIGPIPE_W;
		1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1538
		1539	# not strictly required, as $^F is normally 2, but let's make sure...
		1540	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1541	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1542	}
		1543
		1544	$SIGPIPE_R
		1545	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1546
		1547	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1548	}
		1549
		1550	*signal = $HAVE_ASYNC_INTERRUPT
		1551	? sub {
		1552	my (undef, %arg) = @_;
		1553
		1554	# async::interrupt
		1555	my $signal = sig2num $arg{signal};
		1556	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1557
		1558	$SIG_ASY{$signal} ||= new Async::Interrupt
		1559	cb => sub { undef $SIG_EV{$signal} },
		1560	signal => $signal,
		1561	pipe => [$SIGPIPE_R->filenos],
		1562	pipe_autodrain => 0,
		1563	;
		1564
		1565	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1566	}
		1567	: sub {
		1568	my (undef, %arg) = @_;
		1569
		1570	# pure perl
		1571	my $signal = sig2name $arg{signal};
		1572	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1573
		1574	$SIG{$signal} ||= sub {
		1575	local $!;
		1576	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1577	undef $SIG_EV{$signal};
		1578	};
		1579
		1580	# can't do signal processing without introducing races in pure perl,
		1581	# so limit the signal latency.
		1582	_sig_add;
		1583
		1584	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1585	}
		1586	;
		1587
		1588	*AnyEvent::Base::signal::DESTROY = sub {
		1589	my ($signal, $cb) = @{$_[0]};
		1590
		1591	_sig_del;
		1592
1365	delete $SIG_CB{$signal}{$cb};	1593	delete $SIG_CB{$signal}{$cb};
1366		1594
1367	$HAVE_ASYNC_INTERRUPT	1595	$HAVE_ASYNC_INTERRUPT
1368	? delete $SIG_ASY{$signal}	1596	? delete $SIG_ASY{$signal}
1369	: # delete doesn't work with older perls - they then	1597	: # delete doesn't work with older perls - they then
1370	# print weird messages, or just unconditionally exit	1598	# print weird messages, or just unconditionally exit
1371	# instead of getting the default action.	1599	# instead of getting the default action.
1372	undef $SIG{$signal}	1600	undef $SIG{$signal}
1373	unless keys %{ $SIG_CB{$signal} };	1601	unless keys %{ $SIG_CB{$signal} };
		1602	};
		1603
		1604	*_signal_exec = sub {
		1605	$HAVE_ASYNC_INTERRUPT
		1606	? $SIGPIPE_R->drain
		1607	: sysread $SIGPIPE_R, (my $dummy), 9;
		1608
		1609	while (%SIG_EV) {
		1610	for (keys %SIG_EV) {
		1611	delete $SIG_EV{$_};
		1612	$_->() for values %{ $SIG_CB{$_} || {} };
		1613	}
		1614	}
		1615	};
		1616	};
		1617	die if $@;
		1618
		1619	&signal
1374	}	1620	}
1375		1621
1376	# default implementation for ->child	1622	# default implementation for ->child
1377		1623
1378	our %PID_CB;	1624	our %PID_CB;
1379	our $CHLD_W;	1625	our $CHLD_W;
1380	our $CHLD_DELAY_W;	1626	our $CHLD_DELAY_W;
1381	our $WNOHANG;	1627	our $WNOHANG;
1382		1628
1383	sub _sigchld {	1629	# used by many Impl's
1384	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1630	sub _emit_childstatus($$) {
1385	$_->($pid, $?)	1631	my (undef, $rpid, $rstatus) = @_;
		1632
		1633	$_->($rpid, $rstatus)
1386	for values %{ $PID_CB{$pid} || {} },	1634	for values %{ $PID_CB{$rpid} || {} },
1387	values %{ $PID_CB{0} || {} };	1635	values %{ $PID_CB{0} || {} };
1388	}
1389	}	1636	}
1390		1637
1391	sub child {	1638	sub child {
		1639	eval q{ # poor man's autoloading {}
		1640	*_sigchld = sub {
		1641	my $pid;
		1642
		1643	AnyEvent->_emit_childstatus ($pid, $?)
		1644	while ($pid = waitpid -1, $WNOHANG) > 0;
		1645	};
		1646
		1647	*child = sub {
1392	my (undef, %arg) = @_;	1648	my (undef, %arg) = @_;
1393		1649
1394	defined (my $pid = $arg{pid} + 0)	1650	defined (my $pid = $arg{pid} + 0)
1395	or Carp::croak "required option 'pid' is missing";	1651	or Carp::croak "required option 'pid' is missing";
1396		1652
1397	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1653	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1398		1654
1399	# WNOHANG is almost cetrainly 1 everywhere	1655	# WNOHANG is almost cetrainly 1 everywhere
1400	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/	1656	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1401	? 1	1657	? 1
1402	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1658	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1403		1659
1404	unless ($CHLD_W) {	1660	unless ($CHLD_W) {
1405	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1661	$CHLD_W = AE::signal CHLD => \&_sigchld;
1406	# child could be a zombie already, so make at least one round	1662	# child could be a zombie already, so make at least one round
1407	&_sigchld;	1663	&_sigchld;
1408	}	1664	}
1409		1665
1410	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1666	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1411	}	1667	};
1412		1668
1413	sub AnyEvent::Base::child::DESTROY {	1669	*AnyEvent::Base::child::DESTROY = sub {
1414	my ($pid, $cb) = @{$_[0]};	1670	my ($pid, $cb) = @{$_[0]};
1415		1671
1416	delete $PID_CB{$pid}{$cb};	1672	delete $PID_CB{$pid}{$cb};
1417	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1673	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1418		1674
1419	undef $CHLD_W unless keys %PID_CB;	1675	undef $CHLD_W unless keys %PID_CB;
		1676	};
		1677	};
		1678	die if $@;
		1679
		1680	&child
1420	}	1681	}
1421		1682
1422	# idle emulation is done by simply using a timer, regardless	1683	# idle emulation is done by simply using a timer, regardless
1423	# of whether the process is idle or not, and not letting	1684	# of whether the process is idle or not, and not letting
1424	# the callback use more than 50% of the time.	1685	# the callback use more than 50% of the time.
1425	sub idle {	1686	sub idle {
		1687	eval q{ # poor man's autoloading {}
		1688	*idle = sub {
1426	my (undef, %arg) = @_;	1689	my (undef, %arg) = @_;
1427		1690
1428	my ($cb, $w, $rcb) = $arg{cb};	1691	my ($cb, $w, $rcb) = $arg{cb};
1429		1692
1430	$rcb = sub {	1693	$rcb = sub {
1431	if ($cb) {	1694	if ($cb) {
1432	$w = _time;	1695	$w = _time;
1433	&$cb;	1696	&$cb;
1434	$w = _time - $w;	1697	$w = _time - $w;
1435		1698
1436	# never use more then 50% of the time for the idle watcher,	1699	# never use more then 50% of the time for the idle watcher,
1437	# within some limits	1700	# within some limits
1438	$w = 0.0001 if $w < 0.0001;	1701	$w = 0.0001 if $w < 0.0001;
1439	$w = 5 if $w > 5;	1702	$w = 5 if $w > 5;
1440		1703
1441	$w = AnyEvent->timer (after => $w, cb => $rcb);	1704	$w = AE::timer $w, 0, $rcb;
1442	} else {	1705	} else {
1443	# clean up...	1706	# clean up...
1444	undef $w;	1707	undef $w;
1445	undef $rcb;	1708	undef $rcb;
		1709	}
		1710	};
		1711
		1712	$w = AE::timer 0.05, 0, $rcb;
		1713
		1714	bless \\$cb, "AnyEvent::Base::idle"
1446	}	1715	};
		1716
		1717	*AnyEvent::Base::idle::DESTROY = sub {
		1718	undef $${$_[0]};
		1719	};
1447	};	1720	};
		1721	die if $@;
1448		1722
1449	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1723	&idle
1450
1451	bless \\$cb, "AnyEvent::Base::idle"
1452	}
1453
1454	sub AnyEvent::Base::idle::DESTROY {
1455	undef $${$_[0]};
1456	}	1724	}
1457		1725
1458	package AnyEvent::CondVar;	1726	package AnyEvent::CondVar;
1459		1727
1460	our @ISA = AnyEvent::CondVar::Base::;	1728	our @ISA = AnyEvent::CondVar::Base::;
…		…
1508	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1776	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1509	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1777	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1510	}	1778	}
1511		1779
1512	sub cb {	1780	sub cb {
1513	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1781	my $cv = shift;
		1782
		1783	@_
		1784	and $cv->{_ae_cb} = shift
		1785	and $cv->{_ae_sent}
		1786	and (delete $cv->{_ae_cb})->($cv);
		1787
1514	$_[0]{_ae_cb}	1788	$cv->{_ae_cb}
1515	}	1789	}
1516		1790
1517	sub begin {	1791	sub begin {
1518	++$_[0]{_ae_counter};	1792	++$_[0]{_ae_counter};
1519	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1793	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1581	check the arguments passed to most method calls. If it finds any problems,	1855	check the arguments passed to most method calls. If it finds any problems,
1582	it will croak.	1856	it will croak.
1583		1857
1584	In other words, enables "strict" mode.	1858	In other words, enables "strict" mode.
1585		1859
1586	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1860	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1587	>>, it is definitely recommended to keep it off in production. Keeping	1861	>>, it is definitely recommended to keep it off in production. Keeping
1588	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1862	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1589	can be very useful, however.	1863	can be very useful, however.
1590		1864
1591	=item C<PERL_ANYEVENT_MODEL>	1865	=item C<PERL_ANYEVENT_MODEL>
…		…
1728	warn "read: $input\n"; # output what has been read	2002	warn "read: $input\n"; # output what has been read
1729	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2003	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1730	},	2004	},
1731	);	2005	);
1732		2006
1733	my $time_watcher; # can only be used once
1734
1735	sub new_timer {
1736	$timer = AnyEvent->timer (after => 1, cb => sub {	2007	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1737	warn "timeout\n"; # print 'timeout' about every second	2008	warn "timeout\n"; # print 'timeout' at most every second
1738	&new_timer; # and restart the time
1739	});	2009	});
1740	}
1741
1742	new_timer; # create first timer
1743		2010
1744	$cv->recv; # wait until user enters /^q/i	2011	$cv->recv; # wait until user enters /^q/i
1745		2012
1746	=head1 REAL-WORLD EXAMPLE	2013	=head1 REAL-WORLD EXAMPLE
1747		2014
…		…
1820		2087
1821	The actual code goes further and collects all errors (C<die>s, exceptions)	2088	The actual code goes further and collects all errors (C<die>s, exceptions)
1822	that occurred during request processing. The C<result> method detects	2089	that occurred during request processing. The C<result> method detects
1823	whether an exception as thrown (it is stored inside the $txn object)	2090	whether an exception as thrown (it is stored inside the $txn object)
1824	and just throws the exception, which means connection errors and other	2091	and just throws the exception, which means connection errors and other
1825	problems get reported tot he code that tries to use the result, not in a	2092	problems get reported to the code that tries to use the result, not in a
1826	random callback.	2093	random callback.
1827		2094
1828	All of this enables the following usage styles:	2095	All of this enables the following usage styles:
1829		2096
1830	1. Blocking:	2097	1. Blocking:
…		…
1878	through AnyEvent. The benchmark creates a lot of timers (with a zero	2145	through AnyEvent. The benchmark creates a lot of timers (with a zero
1879	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2146	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1880	which it is), lets them fire exactly once and destroys them again.	2147	which it is), lets them fire exactly once and destroys them again.
1881		2148
1882	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2149	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1883	distribution.	2150	distribution. It uses the L<AE> interface, which makes a real difference
		2151	for the EV and Perl backends only.
1884		2152
1885	=head3 Explanation of the columns	2153	=head3 Explanation of the columns
1886		2154
1887	I<watcher> is the number of event watchers created/destroyed. Since	2155	I<watcher> is the number of event watchers created/destroyed. Since
1888	different event models feature vastly different performances, each event	2156	different event models feature vastly different performances, each event
…		…
1909	watcher.	2177	watcher.
1910		2178
1911	=head3 Results	2179	=head3 Results
1912		2180
1913	name watchers bytes create invoke destroy comment	2181	name watchers bytes create invoke destroy comment
1914	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2182	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1915	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2183	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1916	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2184	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1917	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2185	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1918	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2186	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1919	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2187	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1920	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2188	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1921	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2189	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1922	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2190	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1923	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2191	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1924	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2192	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1925	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2193	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1926		2194
1927	=head3 Discussion	2195	=head3 Discussion
1928		2196
1929	The benchmark does I<not> measure scalability of the event loop very	2197	The benchmark does I<not> measure scalability of the event loop very
1930	well. For example, a select-based event loop (such as the pure perl one)	2198	well. For example, a select-based event loop (such as the pure perl one)
…		…
1942	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2210	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1943	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2211	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1944	cycles with POE.	2212	cycles with POE.
1945		2213
1946	C<EV> is the sole leader regarding speed and memory use, which are both	2214	C<EV> is the sole leader regarding speed and memory use, which are both
1947	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2215	maximal/minimal, respectively. When using the L<AE> API there is zero
		2216	overhead (when going through the AnyEvent API create is about 5-6 times
		2217	slower, with other times being equal, so still uses far less memory than
1948	far less memory than any other event loop and is still faster than Event	2218	any other event loop and is still faster than Event natively).
1949	natively.
1950		2219
1951	The pure perl implementation is hit in a few sweet spots (both the	2220	The pure perl implementation is hit in a few sweet spots (both the
1952	constant timeout and the use of a single fd hit optimisations in the perl	2221	constant timeout and the use of a single fd hit optimisations in the perl
1953	interpreter and the backend itself). Nevertheless this shows that it	2222	interpreter and the backend itself). Nevertheless this shows that it
1954	adds very little overhead in itself. Like any select-based backend its	2223	adds very little overhead in itself. Like any select-based backend its
…		…
2028	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2297	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2029	(1%) are active. This mirrors the activity of large servers with many	2298	(1%) are active. This mirrors the activity of large servers with many
2030	connections, most of which are idle at any one point in time.	2299	connections, most of which are idle at any one point in time.
2031		2300
2032	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2301	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2033	distribution.	2302	distribution. It uses the L<AE> interface, which makes a real difference
		2303	for the EV and Perl backends only.
2034		2304
2035	=head3 Explanation of the columns	2305	=head3 Explanation of the columns
2036		2306
2037	I<sockets> is the number of sockets, and twice the number of "servers" (as	2307	I<sockets> is the number of sockets, and twice the number of "servers" (as
2038	each server has a read and write socket end).	2308	each server has a read and write socket end).
…		…
2046	a new one that moves the timeout into the future.	2316	a new one that moves the timeout into the future.
2047		2317
2048	=head3 Results	2318	=head3 Results
2049		2319
2050	name sockets create request	2320	name sockets create request
2051	EV 20000 69.01 11.16	2321	EV 20000 62.66 7.99
2052	Perl 20000 73.32 35.87	2322	Perl 20000 68.32 32.64
2053	IOAsync 20000 157.00 98.14 epoll	2323	IOAsync 20000 174.06 101.15 epoll
2054	IOAsync 20000 159.31 616.06 poll	2324	IOAsync 20000 174.67 610.84 poll
2055	Event 20000 212.62 257.32	2325	Event 20000 202.69 242.91
2056	Glib 20000 651.16 1896.30	2326	Glib 20000 557.01 1689.52
2057	POE 20000 349.67 12317.24 uses POE::Loop::Event	2327	POE 20000 341.54 12086.32 uses POE::Loop::Event
2058		2328
2059	=head3 Discussion	2329	=head3 Discussion
2060		2330
2061	This benchmark I<does> measure scalability and overall performance of the	2331	This benchmark I<does> measure scalability and overall performance of the
2062	particular event loop.	2332	particular event loop.
…		…
2188	As you can see, the AnyEvent + EV combination even beats the	2458	As you can see, the AnyEvent + EV combination even beats the
2189	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2459	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2190	backend easily beats IO::Lambda and POE.	2460	backend easily beats IO::Lambda and POE.
2191		2461
2192	And even the 100% non-blocking version written using the high-level (and	2462	And even the 100% non-blocking version written using the high-level (and
2193	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2463	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2194	large margin, even though it does all of DNS, tcp-connect and socket I/O	2464	higher level ("unoptimised") abstractions by a large margin, even though
2195	in a non-blocking way.	2465	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2196		2466
2197	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2467	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2198	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2468	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2199	part of the IO::lambda distribution and were used without any changes.	2469	part of the IO::Lambda distribution and were used without any changes.
2200		2470
2201		2471
2202	=head1 SIGNALS	2472	=head1 SIGNALS
2203		2473
2204	AnyEvent currently installs handlers for these signals:	2474	AnyEvent currently installs handlers for these signals:
…		…
2241	unless defined $SIG{PIPE};	2511	unless defined $SIG{PIPE};
2242		2512
2243	=head1 RECOMMENDED/OPTIONAL MODULES	2513	=head1 RECOMMENDED/OPTIONAL MODULES
2244		2514
2245	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2515	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2246	it's built-in modules) are required to use it.	2516	its built-in modules) are required to use it.
2247		2517
2248	That does not mean that AnyEvent won't take advantage of some additional	2518	That does not mean that AnyEvent won't take advantage of some additional
2249	modules if they are installed.	2519	modules if they are installed.
2250		2520
2251	This section epxlains which additional modules will be used, and how they	2521	This section explains which additional modules will be used, and how they
2252	affect AnyEvent's operetion.	2522	affect AnyEvent's operation.
2253		2523
2254	=over 4	2524	=over 4
2255		2525
2256	=item L<Async::Interrupt>	2526	=item L<Async::Interrupt>
2257		2527
2258	This slightly arcane module is used to implement fast signal handling: To	2528	This slightly arcane module is used to implement fast signal handling: To
2259	my knowledge, there is no way to do completely race-free and quick	2529	my knowledge, there is no way to do completely race-free and quick
2260	signal handling in pure perl. To ensure that signals still get	2530	signal handling in pure perl. To ensure that signals still get
2261	delivered, AnyEvent will start an interval timer to wake up perl (and	2531	delivered, AnyEvent will start an interval timer to wake up perl (and
2262	catch the signals) with soemd elay (default is 10 seconds, look for	2532	catch the signals) with some delay (default is 10 seconds, look for
2263	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2533	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2264		2534
2265	If this module is available, then it will be used to implement signal	2535	If this module is available, then it will be used to implement signal
2266	catching, which means that signals will not be delayed, and the event loop	2536	catching, which means that signals will not be delayed, and the event loop
2267	will not be interrupted regularly, which is more efficient (And good for	2537	will not be interrupted regularly, which is more efficient (and good for
2268	battery life on laptops).	2538	battery life on laptops).
2269		2539
2270	This affects not just the pure-perl event loop, but also other event loops	2540	This affects not just the pure-perl event loop, but also other event loops
2271	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2541	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2542
		2543	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2544	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2545	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2546	does nothing for those backends.
2272		2547
2273	=item L<EV>	2548	=item L<EV>
2274		2549
2275	This module isn't really "optional", as it is simply one of the backend	2550	This module isn't really "optional", as it is simply one of the backend
2276	event loops that AnyEvent can use. However, it is simply the best event	2551	event loops that AnyEvent can use. However, it is simply the best event
…		…
2279	automatic timer adjustments even when no monotonic clock is available,	2554	automatic timer adjustments even when no monotonic clock is available,
2280	can take avdantage of advanced kernel interfaces such as C<epoll> and	2555	can take avdantage of advanced kernel interfaces such as C<epoll> and
2281	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2556	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2282	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2557	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2283		2558
		2559	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2560	then this module will do nothing for you.
		2561
2284	=item L<Guard>	2562	=item L<Guard>
2285		2563
2286	The guard module, when used, will be used to implement	2564	The guard module, when used, will be used to implement
2287	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2565	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2288	lot less memory), but otherwise doesn't affect guard operation much. It is	2566	lot less memory), but otherwise doesn't affect guard operation much. It is
2289	purely used for performance.	2567	purely used for performance.
2290		2568
2291	=item L<JSON> and L<JSON::XS>	2569	=item L<JSON> and L<JSON::XS>
2292		2570
2293	This module is required when you want to read or write JSON data via	2571	One of these modules is required when you want to read or write JSON data
2294	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2572	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2295	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.	2573	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2296
2297	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2298	installed.
2299		2574
2300	=item L<Net::SSLeay>	2575	=item L<Net::SSLeay>
2301		2576
2302	Implementing TLS/SSL in Perl is certainly interesting, but not very	2577	Implementing TLS/SSL in Perl is certainly interesting, but not very
2303	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2578	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2304	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2579	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2305		2580
2306	=item L<Time::HiRes>	2581	=item L<Time::HiRes>
2307		2582
2308	This module is part of perl since release 5.008. It will be used when the	2583	This module is part of perl since release 5.008. It will be used when the
2309	chosen event library does not come with a timing source on it's own. The	2584	chosen event library does not come with a timing source of its own. The
2310	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2585	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2311	try to use a monotonic clock for timing stability.	2586	try to use a monotonic clock for timing stability.
2312		2587
2313	=back	2588	=back
2314		2589
2315		2590
2316	=head1 FORK	2591	=head1 FORK
2317		2592
2318	Most event libraries are not fork-safe. The ones who are usually are	2593	Most event libraries are not fork-safe. The ones who are usually are
2319	because they rely on inefficient but fork-safe C<select> or C<poll>	2594	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2320	calls. Only L<EV> is fully fork-aware.	2595	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2596	are usually badly thought-out hacks that are incompatible with fork in
		2597	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2598	continue event-processing in both parent and child (or both, if you know
		2599	what you are doing).
		2600
		2601	This means that, in general, you cannot fork and do event processing in
		2602	the child if the event library was initialised before the fork (which
		2603	usually happens when the first AnyEvent watcher is created, or the library
		2604	is loaded).
2321		2605
2322	If you have to fork, you must either do so I<before> creating your first	2606	If you have to fork, you must either do so I<before> creating your first
2323	watcher OR you must not use AnyEvent at all in the child OR you must do	2607	watcher OR you must not use AnyEvent at all in the child OR you must do
2324	something completely out of the scope of AnyEvent.	2608	something completely out of the scope of AnyEvent.
		2609
		2610	The problem of doing event processing in the parent I<and> the child
		2611	is much more complicated: even for backends that I<are> fork-aware or
		2612	fork-safe, their behaviour is not usually what you want: fork clones all
		2613	watchers, that means all timers, I/O watchers etc. are active in both
		2614	parent and child, which is almost never what you want. USing C<exec>
		2615	to start worker children from some kind of manage rprocess is usually
		2616	preferred, because it is much easier and cleaner, at the expense of having
		2617	to have another binary.
2325		2618
2326		2619
2327	=head1 SECURITY CONSIDERATIONS	2620	=head1 SECURITY CONSIDERATIONS
2328		2621
2329	AnyEvent can be forced to load any event model via	2622	AnyEvent can be forced to load any event model via
…		…
2367	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2660	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2368		2661
2369	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2662	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2370	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2663	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2371	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2664	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2372	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2665	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2373		2666
2374	Non-blocking file handles, sockets, TCP clients and	2667	Non-blocking file handles, sockets, TCP clients and
2375	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2668	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2376		2669
2377	Asynchronous DNS: L<AnyEvent::DNS>.	2670	Asynchronous DNS: L<AnyEvent::DNS>.

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